/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#include "itkAbsoluteValueDifferenceImageFilter.h"
#include "itkImageRegionIteratorWithIndex.h"
#include "itkTestingMacros.h"


int
itkAbsoluteValueDifferenceImageFilterTest(int, char *[])
{

  // Define the dimension of the images
  constexpr unsigned int myDimension{ 3 };

  // Define the values of the input images
  constexpr float input1Value{ 3.0 };
  constexpr float input2Value{ 4.0 };

  // Define the values of the output images
  constexpr float outputValue{ 1.0 };

  // Define the precision for output comparison
  constexpr float epsilon{ 1e-6 };

  // Declare the types of the images
  using myImageType1 = itk::Image<float, myDimension>;
  using myImageType2 = itk::Image<float, myDimension>;
  using myImageType4 = itk::Image<float, myDimension>;

  // Declare the type of the size
  using mySizeType = itk::Size<myDimension>;

  // Declare the type of the Region
  using myRegionType = itk::ImageRegion<myDimension>;

  // Create two images
  auto inputImageA = myImageType1::New();
  auto inputImageB = myImageType2::New();

  // Define their size and region
  auto size = mySizeType::Filled(2);

  const myRegionType region{ size };

  // Initialize Image A
  inputImageA->SetRegions(region);
  inputImageA->Allocate();

  // Initialize Image B
  inputImageB->SetRegions(region);
  inputImageB->Allocate();

  // Declare Iterator types appropriate for each image
  using myIteratorType1 = itk::ImageRegionIteratorWithIndex<myImageType1>;
  using myIteratorType2 = itk::ImageRegionIteratorWithIndex<myImageType2>;
  using myIteratorType4 = itk::ImageRegionIteratorWithIndex<myImageType4>;

  // Create one iterator for Image A (this is a light object)
  myIteratorType1 it1(inputImageA, inputImageA->GetBufferedRegion());

  // Initialize the content of Image A
  std::cout << "First operand " << std::endl;
  while (!it1.IsAtEnd())
  {
    it1.Set(input1Value);
    std::cout << it1.Get() << std::endl;
    ++it1;
  }

  // Create one iterator for Image B (this is a light object)
  myIteratorType2 it2(inputImageB, inputImageB->GetBufferedRegion());

  // Initialize the content of Image B
  std::cout << "Second operand " << std::endl;
  while (!it2.IsAtEnd())
  {
    it2.Set(input2Value);
    std::cout << it2.Get() << std::endl;
    ++it2;
  }


  // Declare the type for the filter
  using myFilterType = itk::AbsoluteValueDifferenceImageFilter<myImageType1, myImageType2, myImageType4>;


  // Create the filter
  auto filter = myFilterType::New();

  ITK_EXERCISE_BASIC_OBJECT_METHODS(filter, AbsoluteValueDifferenceImageFilter, BinaryGeneratorImageFilter);


  // Connect the input images
  filter->SetInput1(inputImageA);
  filter->SetInput2(inputImageB);

  // Get the Smart Pointer to the Filter Output
  const myImageType4::Pointer outputImage = filter->GetOutput();


  // Execute the filter
  filter->Update();

  // Create an iterator for going through the image output
  myIteratorType4 it4(outputImage, outputImage->GetBufferedRegion());

  // Print the content of the result image
  std::cout << " Result " << std::endl;
  while (!it4.IsAtEnd())
  {
    std::cout << it4.Get() << std::endl;
    if (itk::Math::abs(it4.Get() - outputValue) > epsilon)
    {
      std::cerr << "Error in the output" << std::endl;
      std::cerr << "Value should be  " << outputValue << std::endl;
      std::cerr << "but is           " << it4.Get() << std::endl;
      return EXIT_FAILURE;
    }

    ++it4;
  }


  // All objects should be automatically destroyed at this point
  return EXIT_SUCCESS;
}
